/*
 * Copyright 2005-2007 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.ldap.filter;

import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

import org.apache.commons.lang.builder.EqualsBuilder;
import org.apache.commons.lang.builder.HashCodeBuilder;

/**
 * Abstract superclass for binary logical operations, that is &quot;and&quot;
 * and &quot;or&quot; operations.
 * 
 * @author Mattias Arthursson
 */
public abstract class BinaryLogicalFilter extends AbstractFilter {

    protected List queryList = new LinkedList();

    /**
     * @see org.springframework.ldap.filter.Filter#encode(java.lang.StringBuffer)
     */
    public StringBuffer encode(StringBuffer buff) {
        if (queryList.size() <= 0) {

            // only output query if contains anything
            return buff;

        } else if (queryList.size() == 1) {

            // don't add the &
            Filter query = (Filter) queryList.get(0);
            return query.encode(buff);

        } else {
            buff.append("(" + getLogicalOperator());

            for (Iterator i = queryList.iterator(); i.hasNext();) {
                Filter query = (Filter) i.next();
                buff = query.encode(buff);
            }

            buff.append(")");

            return buff;
        }
    }

    /**
     * Implement this in subclass to return the logical operator, for example
     * &qout;&amp;&qout;.
     * 
     * @return the logical operator.
     */
    protected abstract String getLogicalOperator();

    /**
     * Compares each filter in turn
     * 
     * @see org.springframework.ldap.filter.Filter#equals(java.lang.Object)
     */
    public boolean equals(Object obj) {
        if (obj instanceof BinaryLogicalFilter
                && this.getClass() == obj.getClass()) {
            return EqualsBuilder.reflectionEquals(this, obj);
        } else {
            return false;
        }
    }

    /**
     * Hashes all contained data
     * 
     * @see org.springframework.ldap.filter.Filter#hashCode()
     */
    public int hashCode() {
        return HashCodeBuilder.reflectionHashCode(this);
    }
}
